<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>
  <div class="cpu"></div>
  <style>
    .cpu {
      background-color: darkgreen;
      width: 50px;
      height: 50px;
      left: 0;
      top: 0;
      position: fixed;
      animation: move 3.7s ease-in-out infinite;
    }

    @keyframes move {
      25% {
        left: 250px;
        top: 0;
      }

      50% {
        left: 250px;
        top: 250px;
      }

      75% {
        left: 0;
        top: 250px;
      }
    }
  </style>
</body>

</html>